Prediction of Time to Soil Failure Based on Creep Strength Reduction Approach

Soils experience the unrecoverable, continuous deformation known as creep when they are subjected to a stage of constant deviator stress. Creep deformation is due to extrusion of adsorbed water in clay particles, causing the non-recoverable deformation and eventually reduction in the soil shear strength. This study aims to develop a method to determine the creep strength reduction behaviour of soils and prediction of time to occurrence of the creep failure. Case studies on clayey soils including halloysite-rich soil and smectite-rich soil were chosen. A series of triaxial creep tests were conducted in order to obtain the necessary experimental data. Based on the results, the ultimate long-term creep strength or critical stress level of halloysite-rich soil and smectite-rich soil was 85 and 55% of the soil peak strength, respectively. The ultimate time of creep strength reduction in halloysite-rich soil and smectite-rich soil was 10.34 and 46.08 years, respectively. The maximum creep strength reduction ratio of halloysite-rich soil and smectite-rich soil was 0.2 and 0.45, respectively. The developed method allowed predicting time to creep failure of soil specimens.